Added reference to rules to docs for Orchard.Layout
Added reference to rules to docs for Orchard.Layout

The issue in OrchardCMS/OrchardDoc#289 notes that rules/conditions aren't referenced WRT Layouts, even though it's possible to apply a rule to an element. This change rectifies that

abhishekluv/OrchardDoc,OrchardCMS/OrchardDoc,abhishekluv/OrchardDoc,abhishekluv/OrchardDoc,OrchardCMS/OrchardDoc